In the production of many different kinds of products, articles are conveyed along a given path to a machine which performs certain functions or operations thereon. In the case of meat or produce which is commonly placed on trays and wrapped in transparent film for display and sale in a supermarket, trayed product is typically manually located on a conveyor and forwarded to a wrapping machine. At a wrapping station within the machine, a length of film is pulled from a continuous supply roll, placed over the top of the package, cut into a sheet and the package is elevated into the sheet of film. Once elevated, the film is overlappingly tucked under the tray for downstream heat sealing to complete package wrapping.
The mechanism for performing the wrapping is complex mechanically. It requires that the edges of the package be located rather precisely within the machine. The front, rear and side edges must be properly positioned relative to the film sheet which has been created, not only to provide proper overlapping of the film beneath the tray, but also to avoid damage to the packages or machine and resulting lost production. Damage can occur when packages which are misaligned relative to the wrapping mechanism are elevated into operating parts which perform various of the necessary film stretching and tucking functions. The aforementioned U.S. Pat. No. 4,805,760 is a predecessor design of that disclosed and claimed herein and is for the same end purpose.
Other patents which are known to provide the intended function of aligning an article with respect to its conveyor are U.S. Pat. No. 3,089,576 issued to Sauer et al., U.S. Pat. No. 3,194,710 issued to Stremke et al. and U.S. Pat. No. 3,470,997 issued to Trounce, all of which were patent references cited against the '760 U.S. patent noted above.